scary
			 
			 
			
		
		
		
		Maybe shore up the side that is drooping with 2by4's. I really dont think your slab would shift without you noticing some new cracking. I would check out those stands and make sure they are still structurally sound. that is where the problem is most likely located. 
 
Jon 
		
	
		
		
		
		
		
	
		
		
	
	
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